DEĞİŞİK SULAMA REJİMLERİNİN YONCALARIN KÖK AĞIRLIĞI, KÖKÜN KİMYASAL YAPI VE YEDEK BESİN MADDELERİNE KÜMÜLATİF ETKİSİ

Abstract

OZET Degisik toprak derinliklerindeki faydali rutubetin belirli oranlara dustugunde yapilan sulamalar buzlerde yetistirilen iki yillik yoncalarin 0-20 cm. derinlikteki kok agirliklari bu koklerin kimyasal " yapi ve yedek besin maddelerinin agirlik ve oranlari (ham protein orani haric) arasinda %i ihtimal sinir/ari icerisinde cok onemli farkliliklar hasil etmistir. Kok agirligina bagli olarak topraktaki faydali rutubet orani % O' dan % 50 seviyesine arttikca yapilan sulamalarda koklerin kimyasal yapi ve yedek besin maddeleri miktari da artmis, /~ 75 seviyesinde tekrar azalmistir. Ancak oran olarak kimyasal yapi ve yedek besin maddeleri oldukca degisik bir trend arzetmistir. Sulanan toprak derinligi de kok agirligi ve kokun kimyasal yapi ve yed~k besin maddelerine etkili olmus, sulanan toprak derinligi yuzeyden itibaren asagilara inildikce bu maddelerin miktarlari azalmistir. Kuru madde, ham protein, ham seiuioz, ham kul, ether ekstrakt iie elverisli karbonhidrat oranlarinda ise sulama derinliginin etkisi degisik olmustur. SUMMARY The Cumulative Effects of Frequency and Rale of Irrigation on Amounts, and the Chemica! Constituents and Food Reserves of Roots. This research was conducted to investigate the exfects of frequency and rate of irrigation on amount, and the chemical composition, and food reserves in the alfalfa roots which were grown in water-proof cylindrical concrete pots protected from rain. Those pots which were 30 cm. in diameter and 100 cm deep were embeded in soiI with a randomized block design, replicated four times. Differences in frequency of irrigation were determined 0-20 cm., and 50-80 cm. soiI levels. Differences in rate of irrigation were obtained by varying percentage of soil moisture (O %, 25 %, 50 %, and 75 %) at each soil level. There were, therefore, 12 combinations of treatments plus a control receiving only incident ra,in fall. All treatments cut at the end of bud stage. Two cuttings were made in 1966 and four in 1967. At the end of the experiment the roots in the pots were divided into 0-20 cm., 20-50 cm, and 50-80 cm. by cutting. Each part of roots which obtained at the different depth of pots were washed, dried at 78°e and put in the aluininiumcups for analyzing of dry matter, crude protein, cellul03e, ash and etber extract and total available carbohydrates. The following results were obtained from this experiment: i. The effect ofthe different frequency and rate of water supply on the amounts and the ehemical constituents, and food reserves at the 0-20 cm. depth of alfalfa roots was significanL 2. The amounts, and chemieal eonstituents, and food reserves of alfalfa roots were increased in weight in the decreased depth of irrigated soil by inereasing avaible moisture from O% to 50 %' 3. The irrigation regimes effeeted the rate of ehemieal eonstituents and food reserves differently. The rate of ether extract, and total avaibIe earboliydrates increased in general, but dry matter -decreased and there were no effect on crude protein, cellulose and ash in the roots by inereasing avaible water -from 0% to 50 %' The rate of dry matter and crude asli decreased,but crude cellulose inereased and crude proteiii and total avaibIe earbohydrates were not ehanged witli deeper irrigation. 4. In order to maintain a good stand at the limited root growth conduions, it may be reeomended to irrigate when the 50 % of avaible water is present in the 0-50 cm. depth of soiI.